1. Field of the Invention
The present invention relates to a fluid transportation system, and more particularly to a structure of a fluid transportation system which presses an elastic tube by a plurality of fingers in accordance with rotation of cams so as to cause fluid to flow by sequentially closing and releasing the tube.
2. Background of the Invention
A known fluid transportation system (pump) has a tube disposed along a curved and concaved compressed panel and a cam disposed in the vicinity of the compressed panel and the tube. A plurality of fingers are interposed between the cam and the tube. The plural fingers, which are sequentially pressed toward the tube in accordance with the rotation of the cam, compress the tube so as to cause fluid to flow. According to this fluid transportation system, a condition where fluid is caused to flow is produced by attaching the compressed panel to a main body (for example, see JP-T-2001-515557).
According to a fluid transportation system disclosed in JP-T-2001-515557, a tube is inserted into a concave of a compressed panel and the compressed panel having the tube is attached to a main body so as to bring the fluid transportation system into operable condition. Thus, complicated procedures are required before starting operation of the system. In addition, the tube needs to be inserted into the main body in advance when the fluid transportation system is attached to other equipment or installed at a place where handling of the system is difficult.
According to this fluid transportation system, a certain number of fingers constantly close or press the tube while the tube is being attached. Thus, when the closed condition of the tube continues for a long period before operation of the fluid transportation system, the tube is permanently deformed. In this case, flow of fluid is blocked or a predetermined flow amount of fluid is not secured.
Accordingly, the invention has been developed to solve the problems discussed above. It is an object of the invention to provide a compact fluid transportation system capable of preventing permanent deformation of a tube and securing stable flow amount, producing a first condition where a plurality of fingers are all released prior to operation of the fluid transportation system and a second condition where at least one of the plural fingers constantly closes the tube after starting operation of the fluid transportation system.